Britain's Prime Minister Tony Blair is hit with purple powder which was thrown by a protestor as he was speaking in the House of Commons, in London, in this TV image on May 19 during Prime Minister's Questions

On May 19, estranged father Ron Davis stood up in the British House of Commons. Shouting "I haven't seen my daughter for five years," he hurled a condom full of purple-dyed cornstarch at British Prime Minister Tony Blair. The House was evacuated in alarm.

Davis is a member of Fathers 4 Justice, which describes itself as "a new civil rights movement campaigning for a child's right to see both parents and grandparents." Its goal is to eliminate perceived anti-father bias from family court systems in Britain and elsewhere.

F4J's campaign of nonviolent resistance — called "the rising" — has been flamboyant, but it generally has avoided even the appearance of inflicting real harm. The tone is growing angrier. And, although the purple powder caused no injury, it gave that appearance.

How should fathers respond to an "unjust" law? The purple-powder event has thrown that question into debate within the father's rights movement in America.

Some argue that no harm was done and the media paid attention, which was the goal. Others ask, "Will the attention increase or decrease public sympathy for estranged fathers?"

Many movements face a similar debate. My purpose here is not to defend the goals of F4J, though I personally support them. Rather, it is to use them as a springboard to discuss points of strategy. Thus, assuming the goals are worthy and move onto the specific issue, "How should a responsible father respond if he is denied parental rights?"

The first question to ask about any injustice is, "What sort of injustice is it?" Not all violations are equal.

If injustice is defined as the act of denying to someone that which they deserve, then many — if not most — unjust laws have relatively little impact on people's lives. Taxing someone for a government program of which they disapprove and from which they derive no benefit may be unjust. But it also may inflict no great hardship.

Other unjust laws constitute more significant intrusions. But such laws are often difficult to enforce and the consequence of disobedience is rarely felt. For example, some states still restrict common sexual practices, such as oral sex. But, because enforcement is rare and the act of closing the door behind you provides protection, most people do not feel the impact.

At the extreme end of injustice are laws that can neither be avoided nor obeyed without devastating consequences. A divorcing father cannot avoid the family laws that will largely determine all future access to his children. According to a recent survey by the American Association of Retired Persons' magazine, many fathers cannot even maintain access by remaining married. "The Divorce Experience: A Study of Divorce at Midlife and Beyond" found that two-thirds of divorces after age 40 are initiated by wives.

When a divorce cannot be personally resolved, most courts award custody to the mother with visitation rights to the father. Thereafter, fathers — no matter how responsible — can be de facto denied access by ex-wives who ignore visitation rights with impunity. (Ron Davis had court-ordered visitation that he could not get enforced by the English courts.) This constitutes a severe injustice that cannot be tolerated without devastating lives.

In the last few years, that devastation has received increasing attention and public sympathy. Former rock star Bob Geldof, who was knighted for his work with Live Aid, has made headlines by defending father's rights. Of unjust laws, Geldof's campaign states, "When the law promotes injustice, it will fall."

Thus, after determining the severity of an unjust law, the second question to ask is "How and when will it fall?"

For estranged fathers, the "when" is crucial and must be factored into all discussions of "how." Estranged fathers do not have decades to work incrementally toward change. During those decades, their children will grow into strangers. For them, justice delayed is justice denied. Moreover, some laws seem to be increasingly hostile toward estranged fathers. For example, Louisiana has moved to criminalize the non-payment of child support, which hitherto has been a civil matter. Unless the demand to pay child support is linked to reasonable and enforced visitation rights, Louisiana may be criminalizing fathers who simply wish to implement visitation rights and have no other leverage than to withhold payment.

Those who feel impelled to disobey an unjust law have two basic options: nonviolent resistance, or violence.

I commend F4J for pursuing nonviolent resistance, for its march through the streets of London, for picketing family courts, for holding protests outside the homes of "anti-father" judges. It is winning the hearts and minds of those essential third parties of the general public who are beginning to understand the depth and prevalence of anguish felt by estranged fathers.

But F4J walks a perilously thin line by embracing even the appearance of violence. And, in a world now paranoid about anthrax and powder, the protesters in the House of Commons must have known their action would be interpreted as violence.

Appearances have a tendency to become reality and, at the first act of violence by a father's rights advocate, all fathers will suffer. Those who advocate caution are correct to worry.

Wendy McElroy is the editor of ifeminists.com and a research fellow for The Independent Institute in Oakland, Calif. She is the author and editor of many books and articles, including the new book, "Liberty for Women: Freedom and Feminism in the 21st Century" (Ivan R. Dee/Independent Institute, 2002). She lives with her husband in Canada.